I recently added some expansion packs to my 1.6.1v of SparkCDM. Afterwards, any kits that have a 'Plate Reverb' FX either on a single instrument or in the master FX sends will feedback on itself upon loading the kit, making a horrible noise, eventually shutting down audio in spark completely, necessitating a complete reloading of the plugin, or restarting of the standalone app.

This is in OSX 10.8 I haven't bothered to track it to individual instruments because of the fatality of the app as one discovers the issue.